1. Field of the Invention
Exemplary aspects of the present disclosure relate to an apparatus for converting terminal polarity for RS communication, and more particularly to an apparatus for converting a terminal polarity for RS communication configured to automatically convert terminal polarities by analyzing voltage levels of signals, even if communication cables are wired regardless of polarities of terminals.
2. Description of Related Art
RS-485, one of well known serial digital communication systems, is widely used in various fields due to being of fast speed and robust to noise. For example, the RS-485 communication system is widely used for data transmission among control devices in a PLC (Programmable Logic Controller) system. The RS-485 communication uses a differential signal and two signal lines TRXD+ and TRXD−, such that RS-485 communication terminals and cables must be connected with same polarities.
However, wiring errors frequently occur when a network is set up in a complicated system where various devices are mutually connected. If polarities are erroneously connected during wiring works, communication cannot be realized. Particularly, when the RS-485 communication is used for industries, it takes many hours to check wirings, because network scopes are broad, and the system is complicated.